Terbium was discovered in 1843 by C.G. Mosander in Stockholm and was named after the Swedish town of Ytterby. A lanthanide group metal, it is soft, malleable and ductile. Terbium has an abundance of 1.1 ppm in the earth's crust and is found in minerals in combination with other lanthanide group elements. It is slowly oxidised in air, the rate of the reaction being increased if terbium powder is used. Terbium reacts slowly with cold water. Terbium is used in the semiconductor industry as a dopant.Powder - Small particles with an approximately defined size range. Those materials described as alloy precursors are not true alloys - they are made by sintering a blend of powders of the component metals to achieve alloying by diffusion. The resultant cake is ground and sieved to the required particle size range. Unless otherwise stated, the particle sizes shown are for guidance only. We do not guarantee either any particular size distribution between the quoted minimum and maximum sizes, or a specific particle shape.